In order to store a program and data used in a computer with a high reliability, a library apparatus such as a magnetic tape library apparatus is used.
In a magnetic tape library apparatus, a cartridge made by uniting a magnetic tape which is the recording medium and a reel is used in an replaceable manner. The library apparatus includes a cartridge storage shelf (in the following description, it is referred to as “magazine”) which stores a plurality of such cartridges, a drive apparatus that performs reads/writes from/to the recording medium and an accessor mechanism which conveys the recording medium between the magazine and the drive apparatus.
The interior of the magazine is divided into a plurality of cells, and one cartridge is stored in each cell.
The accessor mechanism carries out an operation to take out the cartridge stored in any cell of any magazine and set the cartridge to the drive apparatus. The accessor mechanism also carries out an operation to take out the cartridge from the drive apparatus and store the cartridge into the any cell of the any magazine.
In such library apparatus, the cartridge is replaced as follows. That is, a user draws out the magazine and takes it out to outside of the apparatus. Then, the user replaces the cartridge and inserts the magazine in which the replaced cartridge is stored into the apparatus.
After the cartridge is replaced, the library apparatus needs to carry out an inventory processing. That is, the library apparatus is necessary to perform the inventory processing to acquire information on all the stored cartridges by, for example, reading an identifier of the cartridge from a barcode provided on the cartridge, and to store the acquired information in a memory unit in the library apparatus.
However, along with increase of the volume of data stored in recording media, a large number of recording media have come to be high-densely mounted, and, as a result, there are problems that an execution time of inventory processing is increased and non-actual working hours of the library apparatus is increased.
For example, Japanese Patent Application Laid-Open No. 2011-165239 discloses a technology which realizes reduction of non-actual working hours in the library apparatus when replacing the cartridge. Specifically, a mechanism which enables a part of shelf of the magazine to eject out of the library apparatus and enables to replace the cartridge while continuing an operation of the library apparatus is disclosed.
Japanese Patent Application Laid-Open No. 2009-230839 discloses a magazine holding structure which can change a drawing amount of the magazine step by step with the simple mechanism that has a fewer components.
In the library apparatus disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2011-165239, the number of cartridges that can be taken out at once is small, such as one or two cartridges. Accordingly, because the library apparatus requires large number of times of cartridge replacement, there is a problem that the non-actual working hours is still long.
Japanese Patent Application Laid-Open No. 2009-230839 discloses the technology to change the drawing amount of the magazine step by step in the library apparatus, and the technology to realize reduction of non-actual working hours of the library apparatus is not disclosed.